A contaminated sites glossary. Plain definitions, with sources.

The Alberta ministry that publishes the Tier 1 and Tier 2 soil and groundwater remediation guidelines and the reclamation criteria, and regulates contaminated sites that fall outside the Alberta Energy Regulator's jurisdiction.

Alberta's regulator for energy development, created in 2013 under the Responsible Energy Development Act. It regulates energy projects from application through decommissioning, closure and reclamation, and reviews reclamation and remediation certificates for upstream oil and gas sites.

A firefighting foam for flammable-liquid fires, made by combining hydrocarbon foaming agents with fluorinated surfactants. All AFFF products contain PFAS, which makes airports, fire-training areas, refineries and fuel terminals common PFAS sources.

An area on, in or under a property where contaminants may be present, identified during a Phase I ESA from past or present uses of the property and from potentially contaminating activities. Ontario's site condition regulation defines the term; it is used widely across Canada.

The concentration of a substance that is not caused by the site: either the natural concentration with no human input, or the general level in the surrounding area from diffuse, non-point human sources. In Alberta, background can set the remediation level where it is higher than Tier 1, but it cannot be used to excuse contamination from the site's own activity.

Volatile aromatic hydrocarbons found in gasoline and other petroleum products. They have their own soil and groundwater guidelines and are assessed alongside the petroleum hydrocarbon fractions F1 to F4.

The council of federal, provincial and territorial environment ministers. It publishes the Canadian environmental quality guidelines and the Canada-Wide Standard for petroleum hydrocarbons in soil, which provinces including Alberta build on.

A substance confirmed at a site above its applicable guideline or background level, which the rest of the assessment, delineation and remediation then focus on. Also written as CoC.

A written and visual summary of what is known about a site: the contaminant sources, how contaminants move through soil, groundwater and air, and which receptors could be exposed. It is updated as new data arrives.

Defining the horizontal and vertical extent of contamination above the applicable guidelines. In Alberta, delineation is complete when measured concentrations are below the Tier 1 or Tier 2 guidelines, and it must be finished before remediation starts, except at simple sites cleaned up by excavation.

The field assessment of landscape, soils and vegetation on a reclaimed well site, compared with a representative control area, that shows whether the site meets Alberta's reclamation criteria. Results are entered in OneStop with a reclamation certificate application.

A liquid that does not readily mix with water and is denser than it, so it can sink below the water table and pool on low-permeability layers. Chlorinated solvents such as TCE and PCE, and creosote, are common examples.

The muds and cuttings produced when drilling a well. In Alberta, a Phase 1 ESA for a well site must include a drilling waste disposal assessment before a reclamation certificate can be applied for.

In Alberta's guidelines, a geologic unit above the Base of Groundwater Protection with a bulk hydraulic conductivity of at least 1 × 10⁻⁶ m/s and enough thickness to sustain a yield of 0.76 L/min, or one currently used for domestic purposes, or one AEPA designates. It does not have to be in use today; it is protected for future use.

A measure of the soluble salts in soil or water. For Alberta's soil salinity guidelines, EC is measured in a saturated paste extract and reported in decisiemens per metre (dS/m).

Alberta's main environmental statute. It sets the duty to conserve and reclaim specified land, provides for reclamation and remediation certificates, and underpins the Conservation and Reclamation Regulation and the Remediation Regulation.

The objective of reclamation in Alberta: the ability of the land to support various land uses after reclamation is similar to the ability that existed before the activity, though the individual land uses will not necessarily be identical.

An investigation of whether a site is, or may be, contaminated. In Alberta, minimum requirements for Phase 1 and Phase 2 ESAs are set out in AEPA's Environmental Site Assessment Standard.

Contact between a receptor and a contaminant, for example by swallowing soil, breathing vapour, drinking groundwater or skin contact. Without a complete pathway from source to receptor, there is no exposure.

An Alberta management option where contamination is left in place and risk is managed with barriers, land-use restrictions or ongoing management instead of meeting Tier 1 or Tier 2. Unlike Tier 1 and Tier 2, it does not lead to regulatory closure.

The four carbon ranges used to measure and regulate petroleum hydrocarbons in Canada under the CCME standard: F1 is nC6 to nC10, F2 is >nC10 to nC16, F3 is >nC16 to nC34, and F4 is nC35 and heavier. Lighter fractions are more volatile and mobile; heavier ones persist.

A statistical method that groups samples by similarity, joining the most similar samples and groups step by step into a tree called a dendrogram. In environmental forensics it groups samples with similar chemical fingerprints, which can point to shared sources.

An interpolation method that estimates a value at an unsampled point as a weighted average of nearby samples, with closer samples weighted more heavily. It is simple and fast but gives no estimate of uncertainty.

A geostatistical interpolation method that weights nearby samples using a model of how values are correlated with distance (a variogram). Unlike IDW, it also estimates the uncertainty at each interpolated point.

A liquid that does not readily mix with water and is less dense than it, so it floats on the water table. Gasoline, diesel and crude oil are common examples, and LNAPL is sometimes called free product.

A non-parametric statistical test for a consistent upward or downward trend over time. It compares each result with every later one, does not assume the data are normally distributed, and is widely used on groundwater monitoring data.

A remedy that relies on natural processes, such as biodegradation, dilution and sorption, to reduce contaminant concentrations, with monitoring to show they are working within a reasonable time.

A lab result below the reporting or detection limit, usually written as a less-than value such as <0.5 mg/kg. How non-detects are handled changes statistics, trends and exceedance counts, so they need a stated method.

The Alberta Energy Regulator's online system for applications and submissions, including reclamation certificate applications and Records of Site Condition for oil and gas sites.

Compounds made of two or more fused aromatic rings, such as naphthalene and benzo[a]pyrene. They come from petroleum (petrogenic) and from incomplete combustion of organic material (pyrogenic), and some are carcinogenic.

The route a contaminant takes from a source to a receptor, such as direct soil contact, vapour moving into a building, or groundwater moving to a well or stream. Alberta's guidelines calculate a value for each applicable pathway, and the lowest governs.

An activity on or near a property that may have caused contamination, such as fuel storage or chemical handling. Ontario's site condition regulation lists PCAs, and they are how APECs are identified.

A substance that could be present because of past or present activities at or near a site. PCOCs are identified in a Phase I ESA and tested for in a Phase II. Also written COPC.

Derived from petroleum, such as crude oil, fuels or lubricants. Petrogenic PAH mixtures tend to be dominated by lower-molecular-weight and alkylated PAHs.

A large group of synthetic chemicals with very strong carbon-fluorine bonds, used since the 1950s in products such as firefighting foam, non-stick coatings and stain repellents. They break down very slowly, so they persist in the environment.

The non-intrusive first stage of an ESA: a records review, site visit and interviews to identify actual and potential contamination. In Canada it is often done to CSA Z768; in the US, to ASTM E1527-21.

The intrusive stage that follows when a Phase I finds potential contamination: sampling of soil, groundwater or vapour to confirm and characterize the substances present and how far they extend.

An informal term, used differently by different practitioners, usually for detailed delineation and remedial planning or for remediation after a Phase II. Alberta's ESA Standard defines Phase 1 and Phase 2 only.

The mixture of hydrocarbons in crude oil and refined products. In Canada, PHCs in soil are measured and regulated as the fractions F1 to F4, alongside BTEX.

The zone of contaminated groundwater, or soil vapour, that spreads from a source, typically shaped by groundwater flow.

Formed by incomplete combustion, for example in fires, engines, coal tar or manufactured gas plants. Pyrogenic PAH mixtures tend to be dominated by unsubstituted (parent) PAHs and more four- to six-ring compounds than petrogenic mixtures.

A plan describing how contamination at a site will be remediated or managed, and how success will be confirmed. Alberta's Remediation Regulation provides for remedial action plans and AEPA publishes a guide to preparing one.

The US term, under ASTM E1527-21, for the presence or likely presence of hazardous substances or petroleum products at a property due to a release, under conditions indicative of a release, or under conditions that pose a material threat of a future release.

A person, plant, animal, or resource such as an aquifer or stream that could be harmed by contamination. Guidelines are set to protect the receptors expected for a land use.

Returning disturbed land to an equivalent land capability, for example by replacing soil, restoring drainage and revegetating. It is distinct from remediation, which deals with contamination.

The Alberta certificate confirming that specified land, such as a well site or pipeline, has been conserved and reclaimed. A surface lease cannot be surrendered without one, and the operator stays responsible for surface issues for 25 years and for contamination permanently.

Cleaning up or managing contamination in soil, groundwater or sediment so it meets the applicable guidelines, by excavation, treatment in place or other methods.

A voluntary Alberta certificate confirming that a released substance has been remediated to the Tier 1 or Tier 2 guidelines, either in a defined area (limited) or across a whole site (site-based). It gives regulatory closure for what it names, but does not replace the reclamation certificate.

In Alberta, a form that tracks the progress of assessment and remediation and is submitted with Phase 2 ESA and remediation reports; at the AER it is filed through OneStop as an RoSC. In Ontario, an RSC is a filing in the Environmental Site Registry that summarizes a property's condition, required for some changes to a more sensitive land use.

The ratio of sodium to calcium and magnesium in soil solution: SAR = Na / √((Ca + Mg) / 2), with concentrations in milliequivalents per litre. High SAR damages soil structure. Alberta measures it in a saturated paste extract.

A robust estimate of the rate of a trend: the median of the slopes between every pair of points in a time series. It is often reported with the Mann-Kendall test and is not pulled around by outliers.

A Tier 2 route in Alberta that develops site-specific remediation objectives through a full risk assessment, used for complex sites, unstable parameters or direct measurements at the point of exposure such as soil vapour.

Alberta's generic, risk-based soil and groundwater remediation guidelines: conservative values chosen by land use, soil texture, depth and water use. The lowest value across the applicable exposure pathways is the guideline.

Alberta's site-specific guidelines: Tier 1 modified with site facts, by excluding pathways that cannot operate or using measured, stable site parameters, at the same level of protection. Tier 2 can be stricter than Tier 1 on a sensitive site.

An Alberta letter confirming that an area already meets the Tier 2 guidelines and needs no further work. It gives administrative closure, not the regulatory closure of a remediation certificate.

A dimension-reduction technique that maps data with many variables, such as dozens of analytes per sample, onto two or three dimensions while keeping similar samples close together. It is used to see groups of chemically similar samples.

The movement of volatile contaminants from soil or groundwater up into buildings, where they can affect indoor air. Alberta's guidelines include an indoor vapour inhalation pathway for it.

Carbon-based chemicals that evaporate readily at normal temperatures, including BTEX and chlorinated solvents such as TCE and PCE. Their volatility drives the vapour pathways.